2-Chloro-3,3,3-trifluoropropene (HCFO-1233xf) represented by the chemical formula: CF3CCl═CH2 is a compound that is useful as an intermediate for producing various kinds of fluorocarbons, and also as a monomer component of various kinds of polymers.
A known process for preparing HCFO-1233xf comprises reacting some material with anhydrous hydrogen fluoride (HF) in a gas phase in the presence of a catalyst. For example, Patent Literature (PTL) 1 listed below discloses a process comprising fluorination of 1,1,2,3-tetrachloropropene (HCO-1230xa, CCl2═CClCH2Cl) in a gas phase using a chromium-based catalyst. Patent Literature 2 listed below also reports a process comprising fluorination of 1,1,2,3-tetrachloropropene in a gas phase using a chromium-based catalyst. Further, Patent Literature 3 teaches that 1,1,2,3-tetrachloropropene (HCO-1230xa), 1,1,1,2,3-pentachloropropane (HCC-240db), 2,3,3,3-tetrachloropropene (HCO-1230xf), etc., can be fluorinated in the presence of a stabilizer for minimizing catalyst deterioration.
However, the processes disclosed in the above literature have various disadvantages. For example, further improvement in the yield of HCFO-1233xf is required, use of a catalyst is costly, and many products are produced by the reaction in addition to the target product of HCFO-1233xf, resulting in unsatisfactory selectivity. Further, since catalytic activity tends to decrease as a reaction proceeds, there have been many attempts to use a stabilizer for the purpose of minimizing catalyst deactivation.
Patent Literature 4 discloses a process comprising reacting 1,1,2,3-tetrachloropropene (HCO-1230xa) with anhydrous hydrogen fluoride (HF) in a liquid phase in the presence of a halogenated antimony catalyst. However, this process is unsuitable for industrial production, because handling the catalyst is difficult, the process is uneconomical due to the occurrence of reactor corrosion, necessity for waste treatment, etc., and its operation is problematic.
Patent Literature 5 reports that HCFO-1233xf can be prepared by reacting 1,1,2,3-tetrachloropropene (HCO-1230xa) with anhydrous hydrogen fluoride (HF) in a liquid phase in the absence of a catalyst. However, this process is not suitable for industrial-scale production because a longer reaction time is required as a result of its low reaction rate, an overly large amount of HF is necessary, severe reaction conditions under high pressure are necessitated, etc.
As described above, a process by which HCFO-1233xf is easily and economically prepared at a high yield has not yet been established.